The four cross sections shown in fig $6\mathrm{.}15$ belong to four different beams with f$\text{'}$c $=4$ ksi, fy $=60$ ksi,

a$.)$ Check the spacing of the bars in each section according to ACI Code requirement using fs $=0\mathrm{.}6$fy$.$

Figure $6\mathrm{.}15$